How about if it goes a little faster?

Installing a new control system
Coffee, amongst other things, is packaged at Ahold Delhaize Coffee Company (ADCC) in Zaandam. Coffee in pads, in cups, ground coffee and coffee beans. For many years, coffee beans have been roasted, ground into various levels of fineness and every day a substantial number of lines are ready to automatically fill the packagings. More and more automated and with a constantly increasing use of modern technologies. Sometimes forced, because what if the components for your control system are no longer available? In those circumstances you are forced to convert to a new system. And what if there are no functional specifications for your current installation? Then you might need some additional time for the conversion.

Stefan de Boer is project engineer and schooled as a control system engineer. A wide concept. At ADCC he deals with many different components, from complete production lines to packaging lines. Sometimes he takes charge of a project, and sometimes he “just” helps out. He has been working for years on a particular line in “his” factory – of which there are no fewer than three in operation. The control system of this packaging line – a vertical forming, sealing and closing machine that packages beans in bags – was customized by the supplier a long time ago. When the time arrived to adapt the machine, it wasn’t quite as easy as De Boer had expected. “According to the supplier, the components of the control system were no longer available, so it had to be completely replaced and this wasn’t possible on site. In other words: The complete line had to be dismantled and taken to the supplier’s factory in order to convert it there. You can imagine that this wasn’t exactly something we were thrilled about. Not only because of the high costs it involved, but also because of the fact that this line would then probably be out of production for months.”

No specifications
De Boer decided to ask the integrator, VSE from Schoonhoven who he had had plenty of experience with, for their ideas. “I had already had previous experience with them and we speak the same language, which is great. In an earlier project, which concerned upgrading a line for filling coffee pads, we came across a control system with a number of old servo drives and servomotors that were no longer available. In order to ensure continuity, they then replaced them for us. For this, we chose Siemens’ Simatic Motion system and VSE proved to be able to deal with this very well. This experience was such that we went to talk to them again and again chose the same system to upgrade this project.”

Faster packaging required
“As we didn’t have any specifications of the original control system and it wasn’t possible to identify them, we actually had to start from scratch. This was quite a challenge because the technology of the new control system was different, the process for each product had to be re-selected and there is a huge diversity of products that could be used on this one line. There are as many as thirty "recipes" that need to be configured. Just working out all the parameters took weeks. The software connection for all the motion technology had to be written completely and at the same time we chose not just to make the line suitable for coffee beans, but also to process the ground coffee.”

Now that the line has been converted, it has a much higher capacity – solely thanks to the improved technology. De Boer: “The next step is the packaging line, because the speed at which the line can run is now limited by the packaging capacity. The maximum number of products could be increased by fifteen to twenty percent, but that has to processed at the next stage.” That next step, the packaging line, is high up on the wish list. “The best thing about the whole process is when you see the engineers at work, with a huge spaghetti of wires in front of them on Monday and by Thursday they have managed to turn the same spaghetti into neat orderly wiring which is been tested under voltage. And if the software is installed on Friday, then you get that they know what they’re doing.”

Jelle Verwoerd from VSE talks about the approach. “For Ahold Delhaize it was paramount that the new control system had to be reliable. They had already had a positive experience with the control system and that’s why they chose to use it again on this line. First and foremost because their own mechanics are already familiar with these systems and secondly because of safety and reliability.” Given that there was no functional description whatsoever available for the control system, Verwoerd started by taking notes when the machine was running. “That was a significant challenge. It wasn’t, after all, only the various motors that needed to be connected in the software, but also all of the other control elements, such as the pneumatic elements, degassing valves, the control of the filling machine, the opening and closing of the muzzle, the labeler and CO2 gas unit. Many of these elements also needed to be coordinated with each other with the timing being a critical factor. If the coffee is filled into the foil too early, the packaging is not airtight and will be rejected.”

A complex unit, as it turned out. “However well we observed during operation, there ultimately appeared to be even more functionality than was visible. We therefore needed to incorporate new solutions on the go. And the dual function, that means we can process ground coffee and beans on the same line, was an additional challenge.”

Time-critical adjustment
Verwoerd: “Given that certain elements need to be coordinated with each other with the timing being such a critical factor, you need to very closely match this in the software. Before the seal is made, a check is performed to make sure there is no coffee in the seal. The seal always closes precisely at motor position zero. The positioning of this motor largely determines the quality of the cross seal. And particularly with this seal, the power, time and temperature of sealing is vital. If the motor position is 0.01, the seal is not completely closed. We therefore had to figure out exactly what needs to be correlated with what. In those thirty recipes that Stefan de Boer mentioned, all the configurations are set for each product.”
He continues: “For example, the sealing of the film on the muzzle is done using a servomotor. The force of the sealing needs to be very consistent. We initially did this with position control, to zero. However, due to differences in the mechanics, we now control this via the motor torque, with power on the muzzle. And that’s why we had to reconsider absolutely everything for each individual part in the whole process. We certainly slightly misjudged the fact that this could give such a diverse total picture for every recipe. And having thirty-one recipes on the machine means that ultimately most of the time is spent on getting this right – the conversion itself was completed within a week. But the adjustment subsequently had to be performed per recipe. It proved not to be a matter of weight versus product type in these parameters. Because the same was true for dosing, weighing, the printer, labeler and the discharge line. All these elements need to run synchronized for each recipe.”

“We managed to configure everything together with the client’s technical department. And the operator is now pretty happy because changing the recipe is now a piece of cake thanks to the new equipment. However, that's not the only improvement he has benefited from. The temperature regulations were previously separate by means of a PID controller, and now they are integrated in the PLC and can be read via the HMI. The failure diagnosis has also been massively improved and the equipment has integrated safety.”

De Boer is very pleased with how it eventually turned out. “The fact that it took so much time with the recipes was a bit of a setback for us all, but that has been more than solved now. We felt completely in the dark at the beginning due to the lack of specifications, but now, after sorting the first one, we have a really good basis for converting the next lines.” A second line has been converted in the meantime. “We could now use one-to-one settings which we puzzled on so long with the first one and it was fixed just like that. That packaging line is moving higher and higher up the list!”

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